Dental hand piece



Oct. 16, 1934.`

L. KJQCAMPBELL DENTAL HAND PIEQE Filed July l5, 1931 Yu. E

Patented Oct. 16, 1934 f UNITED STATES PATENT OFFICE 2 Claims.

` Y An object of my invention is to providea dental Y hand piece with a control switch associated.

therewith, the device being of simple, durable and comparatively inexpensive construction.

g; I A further object is to provide a control switch for the electric tool motor commonly used by dentists, which is built into the dental hand piece soothat it can be controlled by hand, thus eliminatingthe foot switch and rheostat now used for 10` controlling such motors.

A further object is to provide a switch in the dental hand piece arranged to control starting, stopping, speed and reversal of the tool motor `from the dental hand piece, which does away l5 with the placing of the bulk of the dentists weight upon one foot ,which is necessary with the foot operated type of control to have rapid and complete control of the regulation o f the tool motor with his other foot. Foot operation causes `20 the dental operator to become fatigued, which l is not conducive to health and when standing on one foot, he is offy balance, ywith the result that it is diflicult to accurately control the position ofthe tool in the patients mouths, especially 25 when they happen to jerk their heads. When a 35 by to control starting, stopping and the speed ofthe tool motor. Still a further object is to provide additional `4s`contacts for controlling the reversal and the l ,reverse speed of the `tool motor.

Still another object is to providefa reversing switch, whichA isof therelay type, whereby to make it possible to eliminate theinclusion of a l reversing switch and ther complication of detailsl u attendant therewith if an attempt were made to a 45 build the reversing switch in the dental hand piece and thus I am able to keep the size of the hand piece rwithin reasonable limits and of convenient rather than `awkward size.

With these and other objects in view my invention consistsin` the construction, arrangement and combination of the various parts of my dew vice, whereby the objects contemplatedare attained,A as hereinafter more fully set forth,` pointed out in my claims, and illustrated in thek (S5v accompanying drawing, in which:

(Cl. 32-15) l Figurel is a plan view of a dental hand piece embodying my invention.

Figure 2 is a vertical longitudinal sectional View through the same.

Figure 3 is an enlarged sectional view of a portion of a sleeve shown in Figure 2.

Figures 4 and 5 are enlarged sectional views on the lines 4-4 and 5-5 respectively of Figure 2.

Figure 6 is a perspective view of a movable contact. l

Figure 7 isan electric diagrammatic View of the hand piece and the electric tool motor and associated Darts; and

Figure 8 is an enlarged sectional view as taken on the line 8-8 of Figure 2, illustrating a modified form of construction.

On the accompanying drawing, I have used in the diagrammatic Figure 7, the reference numeral l0 to indicate the base of a dental machine. A base of this character supports an electric tool motor M and has extending therefrom, arms 12 and 14, which are jointed. A dental hand piece indicated generally at A, is connected by a joint with the end of the arm 14 and has a tool drive shaft 16, which is operatively connected by a pulley 18 and a belt (not shown) with themotor M. The foregoing parts are of general dental machine construction and form no part of` my present invention.

The dental hand piece A includes a foundation sleeve 20, preferably of insulating material, which is connected, as by screw threads 22, with a head 24 on the end of the arm 14. The foundation sleeve 20 may be secured relative to the head 24 by a pin 26, which is held in position by a bear 99 ling sleeve 28. The bearing sleeve 28 is screwed into one end of the foundation sleeve 20.

Rotatably mounted on the foundation sleeve 20,

` I provide a hand hold sleeve 30, which is retained against longitudinal movement by a retainer nutY 32. .A tool head 34 is connected with a tapered extension 36 of the hand hold sleeve 30 and is non-rotatable relative thereto, as will hereinafter be described.r l

The drive shaft 16 has a reduced portion 16a journalled in the bearing sleeve 28 andconnects with a tool shaft 38 extending through the tool head 34. A tool, such as a burr 40, is operatively connected Ywith the tool shaft 38 in the ordinary manner, the tool head 34 being of standard construction. f

The hand hold sleeve 30 is preferably of insulating material and has molded therein, a metal insert 42 which constitutes a guide for a movable contact 44. The insert 42 has a guideway 110 46 for an enlarged blade 44a of the contact 44 The coilectorrings have corresponding indicia to slide through, a slot 48 being provided for the along the insert 42 aS Shown in Figure 1, So that reduced portion 44h of the contact 44 to extend the operator Can determine What Speed he S through. operating the motor at and these serve as a guide The foundation sleeve 20 is provided With colt0 illdieate the proper positions for Various Speeds, 80

Y lector rings l, 2, 3, 4, 1R and 2R, The Contact 44 for stoppingand for reverse. In the installation has a contact portion indicated at 44e for seme; thus far described, the machine 10 is grounded to tive coaction with the collector rings, which is eliminate any danger of Shook to the Operatormade possible by the sliding arrangement of -the @Inn Some instances, electrical code requirements 1o contact14'4--with respect to theY metal insert`-42. donot tolerateexposuresofoneof 'the circuit 85 The insert 42 has a cover portion 42a fortheeen-` .wires, as by grounding it through the machine larged part 44a of the contact 44, when the conand I have therefore made provision for insulattact portion 44o is adjacent oit, 1R ore-"2R,1v ring the contact 44 as shown in Figure 8. The hand positions. The Contact 44 is made of springmafA hold sleeve 30, it will be remembered, is of insulatterial and normally assumes a position spaced ing'niat'erial. It iS illustrated in Figure 8 at 90 from the collector rings, as shownlinlligur 2.- f 'f-30lfas` having Slots 33 provided With metal n- From the foregoing descriptionnt-wiu be obviseits` 90 v15o-Ceara With the Contact blade 44- ous that the contact portion`44c`of'the`cotac't`44 "Th'eiIiS'ertS" 90 are Completely Concealed in the (which has a knurled head) may be ,engaged'lby insulating sleeve 30a and the contact blade 44 a linger or thumb of the dental operator and the iS insulated by Strips of inSillatiori92-- The iii- 95 -flfcontactcan be botnslidrelativeto theV4 insert 421-r` sulati'onf92 mayfberetainedinrfpostionby'ivets and pressed to engage the collector 'rings'as vde.'lf-"294,11the s heads 'of lwhich; are insulatediromfthe 1' -sired.- This can easily bel'donewith the handi'blade 4'4Fbyfinsulationf`96.- Itwillibe-noted-Y that which is holding the handpiece. l theholesfirr the 'bla'de44iare 'suiciently/largeto '25 l The collector rings are connectedy with wiresf y'v prevent lcontacto'fv-lthe rivetswith the blade- In 100 5o, which extend* longitudinally vthrough the ethis'tyne ofhand'pieoe;fan insulatedfwrelextends f `-foundationsleeve 20 and into an^annularlpocket*through the oable 54 andis connectedwith" the 52L 0f the Ahead v24. f' Thewires 50v are insulatedinserts 90,*so'that the currentiiovvs through this UA*where they extend from'the Vfoundationsleeve 20-`-'Wire b'and-litheinserts :ratherthan through" theH i530 and into the pocket 52 and all extendV into a cable frame of the machine and? thus fulliin'sulation ii105 E54. The v:metal insert 42 is grounded With relationi'obtained.' fr -1 L ,i vl `lv`to 'the metal of the dental machinel by--me'ans 'I*From-the-deSCi`iDtion-ofmy dental handpieoa of a lug 56 which contacts'with the'f-bearing'itWillfbe obvious thatIhaVeDroVid-ed anefoient tesleeve' 36, the sleeverbeingincontact A'with the:-YcontrolIbuiltintoadihandfpiece:of:normal-isize, shorties. The lug 56 alsoextends into a notches Hwithprovision for'StartinefandStopping the t001211o of the metal tool head-34. KJAlllsi'lally-the tool heady S motorv and' Controlling "tS Speed of frotatonfes s V34Y is-not used (except for Y back teeth) the'tool 40 welloas; its reversaLiflBy the'l provision-'of al relay "being `extended intofthe sleeve; y36jandy direct-lactuatedfreversing switch, al multiplicityof mov- V"connected with the drive shaft-16 by a clutchl-#able contactsinconnectionivwiththehandrpiece is *340' rod 19" and clutchY knob 21. AElectricv current isireliminated. Y x i115 supplied `from the frarneofv themachinel f10 I hefoolleotor fri-IigSf-*areprovidedini-theiform through thev armsY 12 and'14 andthe shaft 4161130 ril-lgsl yS01'1hat`'leiilolity` oftheif'hand` Dieoe iS e "the lug 56.` t Y :#isecuredisinc'e `:itr` is ottoni-desirable tonrota'te Athe I llfliand-hold-sle ive 530 v.relativeto-the"foundation cwcmtgn'angemmt i -l!=sleeVe='20.v II'husby having the-collector rings dfl-f120 In` Figure 7, I 4"have illustratedffthe` circuitannular#bonstruction;v contactfmaybe Smade re- Afarrangernent ofemy dental hand-piece inconnecJ-flgardle'sslof lthe l rotatable position` ofi-the sleeve imtion 1with VaV shunt Wound motor.` ejjwires 50-f30frelative` toi the sleeve 20; "Any numberloffcolextending fromthecollectorjrings -1, '2;'3fand 4*l'ecto1 ringsmaybe used. f J f 1 Y 5q-are connected-with aL rheostatjwinding i60; while 'y @Some changes may be made'in `the;construction?125 i A"the Wires from they collector-rings 1R Vand' 2R ``and"afrrange'rnent of @thepartsv of; my device- With- "are connected' with a rheostat winding l62. The-outedepartin'g fror the'real'spirit 'and'y purpose of Winding j is connected jwith thearmaturefj64 myririventi'ongadl it islmy` intention-*to -coverfby Aofthe motor Mand through a* reversingV switch Bj'- my'cl'a`inis,ffIany-v modiedl'formsof structur-or *euse `of-1me`chanical`equivalents, which mayv be'l13@ e355 E`Wit`hftl 1 'e iield'coiliofthe motor. l LThe reversingsvvitch B`comprises'switch: blades reasonably included Within their'scope.

68 and 70 operatively-connected together with a ll-claimfasiny invention: y

AIVb ar72andvv normally 4en gageable Withfcontacts 74 1i; `v4 Io1--'i1s'ewith-leent'` electric-tooimotor, Ya? re- WJa'ndfti due to the action of' a'spring 78.' Versing switch therefor-`havinga relay coilwand a i060 This causes ow of current in AVone direc-tion*rlieostat"windingforsademotorya-dental hanie135 L through Athe eld coil66 when the contactjportion f'piece comprisingfalfoundation' sleeve, -a='plurality 44cfis in Contact l'vvithj any ofA the contactsij 2,"' of lo'ngitudinal1y spacedicollector *rings thereon, -y3f-`or 4r lThe lcontactportion?44e, itwillbenoted,af'hand lhold sleeve rotatably mounted on said ,is of vs uilicient Width to `bridge"-twojeiadjeicent- `foundation 'slee-ile; v'ai contact-su`11iportedn on'said contacts-exceptland 1 R)*so that achangeffrom 1hand'h`old sleeve;andflongitudinally slidable' ref-@40 *onecollector ringto another maybcemadetwith- -ativefbtheretdjf said t."corita'ct 1 being selectively for swinging the switch blades 68 andf'loftoen-rota'tion of'said"motor.V i I' l Agage with contacts 84 and 86 against the action of l 2;` Forfuse with anv j electric @tool lmotorgf a thelspring 78; 4This causes a reverse flow'of ythe"ireversing switch;'airelayforithetreversing switch,

currentthroughthe"lieldcol 66, thusy Areversi'ngc'and arriheostat .Windingfor thefmoton'f af' dental 175#therotationiofffthefmotor'M. .I hand piece comprising affoun'dationsleevef-ofrizi 150 lector rings and Wiring through said foundation sleeve for including said collector rings in the circuit of said motor and said rheostat winding, whereby to control the speed of said motor, said contact being also included in said circuit.

LESLIE K. CAMPBELL. 

